This proposal is to participate in a Transfusion Medicine/Hemostasis Clinical Research Network. The proposal is submitted by the Transfusion Medicine Division of the Johns Hopkins Medical Institutions (JHMI) with specific collaborations from the Hematology divisions of the Departments of Medicine and Pediatrics (responsible for the management of sickle cell anemia and hemostatic disorders), the Department of Anesthesia and Critical Care Medicine, the Hematopoietic and Therapeutic Support service (HATS) (a joint program of the Departments of Pathology and Oncology), and the Advanced Transfusion Practices (ATP) Center at JHMI. The JHMI core clinical center will coordinate the activities of individuals with expertise in transfusion medicine/hemostasis, taking advantage of pre-existing links between the JHMI departments and programs, and utilizing a large and diverse patient base whose therapy is highly dependent upon transfusion and hemostatic therapies. The Hopkins team will participate with other institutions and the coordinating center of the network, proposing study protocols and amending protocols suggested by collaborating institutions. The proposal describes two clinical protocols that could be selected by the clinical research network. One study will focus upon the transfusion needs of patients with sickle cell anemia in the perioperative setting using hemoglobin based oxygen carriers as one therapeutic option compared to transfusions. A second protocol will study a widely used but incompletely evaluated alternative to transfusion, acute normovolemic hemodilution (ANH), whose efficacy and adverse event profile is unclear. If the ANH procedure is efficacious, and important element is its provision of fresh autologous blood elements to reduce bleeding in perioperative patients, an important hemostasis endpoint.